The Effect of Galaxy Environment on Star Formation inGalaxy Pairs

摘要

We analyze star formation rates in pairs of galaxies in different en-vironments using the 2dFGRS and SDSS-DR2 galaxy surveys. The two samples,comprising 9181 and 11274 galaxy pairs respectively, are suitable for exploringthe dependence of star formation activity in pairs on orbital parameters andglobal environment. We use the projected galaxy density derived from the sixthbright neighbor of each galaxy to define the local density. For both surveys,star formation is found to be a strong function of the global environment andorbital parameters. We find that galaxy interactions are more effective in stim-ulating present-day star formation in low and moderate density environmentswith respect to the control sample of galaxies without a close companion.